The known sterilizing devices for so-called point-of-use application, i.e., application at the site of use, are chamber reactors, which generally consist of stainless steel or aluminum. The reactors are often cylindrical in shape and have two connections for the water inlet and for the water outlet. At the outlet a line is connected, leading to the tapping site. In the middle of the reactors there is a linear low-pressure mercury lamp. This UV lamp must be replaced at regular intervals in order to make sure that the required radiation power is always available for an effective sterilization.
From U.S. Pat. No. 4,769,131 there is known a sterilizing apparatus in which a UV lamp is arranged centrally in a housing, being surrounded by a tube coil, ending in corresponding connection fittings in the wall of the housing. The turns of the tube form the reaction chamber and are irradiated by the UV lamp. To replace the lamp, a plate at the end of the housing has to be removed. The lamp is then drawn out from inside the tube coil.
The outlet can be connected directly to a water faucet or other suitable means of removal. These downstream components can provide additional sterilization. In addition, a traditional filter cartridge can be installed upstream from this sterilizing apparatus.
The reaction chamber can also be formed by grooves in the housing of the sterilizing device. In this case, the UV lamp is surrounded by a two-piece housing envelope.
From U.S. 2004/0182761 A1 there is known a sterilizing unit that provides a combination of filter and UV lamp. In a water conducting housing there is arranged, among other things, an annular carbon block, in which the UV lamp is placed. To replace the UV lamp, one must first open the housing and then remove the carbon block from the water located in the housing. The water located in the carbon block drains out when it is removed from the latter and contaminates the surroundings of the unit. Several manual operations are required before the UV lamp being replaced can be reached. Furthermore, the water conducting parts of the unit are exposed and grabbed by the user and therefore contaminated when replacing the carbon basin and/or UV lamp.
Another drawback is the design-related large space required by the unit, as well as the space required for inserting and removing the UV lamp. A final installation in familiar water-dispensing units is not advisable, because the space required at the tapping site would be very great. It is impractical, unaesthetic, and economically inadvisable. Examples of this would be installation in a water dispenser integrated in the door of a refrigerator or an installation in a water cooler with the dimensions of a table-top appliance.
Furthermore, the internal volume of the chamber is large in the appliances of this and the preceding document. This has the disadvantage that such sterilizing units are difficult to operate downstream from a unit that produces chilled drinking water. For the water in the reaction chamber of the sterilizing unit is generally located outside the refrigerating space and becomes warm. Furthermore, none of the known appliances have the ability to chill the water in the reaction chamber and/or the lamp by a cooling element, such as a heat dissipater.
From EP 1 440 941 B1 there is known a water treatment apparatus for beverage dispensers for serving drinking water. The appliance comprises a segment of a water pipe as the reaction chamber, with a UV lamp arranged upstream from the outlet of the water pipe, which forms a tapping site for the removal of the sterilized water, and parallel to the water pipe. The tapping site itself is located outside of the irradiation range of the UV lamp and provided with a protecting element to protect against being contaminated by the user.
The UV lamp can only be replaced with relatively great effort when needed. The reaction chamber is obviously permanently installed and therefore needs to be cleaned from time to time. However, no explanation of these issues is found in EP 1 440 941 B1. The sterilizing power of this appliance is poor in relation to its size, because the reaction chamber is only partly filled with water due to the air inlet situated on top.